Introduction Outdoor smoke-free policies (SFPs) at sports clubs may contribute to the prevention of smoking among adolescents. Adolescents’ support for such policy is important to its success. The aim of this study is to explore adolescents’ perceptions with regard to an outdoor SFP at sports clubs in the Netherlands. Methods Focus group discussions (n=27) were held with 180 participants (aged 13–18 years) at 16 sports clubs. Thematic analysis was used to analyze the data. Results Participants generally supported an outdoor SFP at sports clubs. Five reasons for this support were reported: 1) children should not be exposed to smoking, 2) smoking and sports (clubs) do not fit together, 3) secondhand smoke is undesirable, 4) an outdoor SFP may enhance a sports club’s image, and 5) an outdoor SFP contributes to the prevention of smoking. Some participants voiced considerations against an outdoor SFP, arguing amongst others, that smokers need to be taken into account, and that problems may occur with compliance and enforcement. Support for an outdoor SFP was stronger among participants at clubs with an outdoor SFP than among those without such policy. Conclusions This study shows that adolescents generally support an outdoor smoke-free policy at sports clubs. After implementation, the outdoor SFP was generally experienced as a normal practice. These results could encourage sports clubs without an outdoor SFP to become smoke-free as well.